The solar system is being spring-cleaned. Jupiter's moons are to be drastically reduced in number to improve its feng shui. But with eco-terrorists taking an active and deadly interest in the work, corrupt officials lining their own pockets, and incompetence leading to the demolition of the wrong moon, the Doctor, Fitz and Trix realise that not everything is as aesthetic or as innocent as it seems...
Fitz and Trix.
Pg 10 Inside a loading bay aboard a space station orbiting Saturn, c 2338 (but see Continuity Cock-Ups).
Parallel 59 might be helpful, if you're in a Blake's 7 mood.
This book exists solely to correct a scientific error from Revenge of the Cybermen (as mentioned in the Afterword), but that isn't necessary.
Pg 6 "'Actually, some mercury would be very useful right now,' said the Doctor. 'Does anyone have a little they could spare? It's for the fluid links, you see...'" The setup of this book mirrors that of The Daleks, whereby the TARDIS's fluid links need mercury and the search for it leads to a complicated adventure. Given that The Daleks was the second story and this is the second-last EDA, that's probably no coincidence. The fluid links and the mercury form the ongoing running thread of the TARDIS crew's motivation throughout this story, so I haven't noted the other mentions.
Pg 34 "Hey, pity they couldn't get old Welwyn Borr to help them out, isn't it?" The Tomorrow Windows (page 117).
Pg 38 "I studied that for a while in Peking during the roaring Twenties..." presumably during the Earth Arc (The Burning through Escape Velocity).
Pg 41 "Maybe his old mum, kind and restored, was coming our to meet him." We met Fitz's mum in The Taint.
Pg 56 "A wise man once said that all you needed to succeed in life was a good idea - and it didn't necessarily have to be your idea." The wise man in question was actually Doctor Who writer Malcolm Hulke and the quote is one frequently related by fellow writer Terrance Dicks.
Pg 57 "He started out gently, kitting out the first room like a dwelling on Mechta - a quite literally mental place where, nevertheless, he'd been happy for a while." Parallel 59.
"Fitz squashed a slightly sanitised version of Il-Eruk's tavern on Yquatine onto its contours." The Fall of Yquatine.
"His parting shot, the coup de grace, was a recreation of the Council of Eight's hourglass room, a crystal chamber with shelves and shelves of twinkling timepieces - in an unsettling shade of mauve." Sometime Never...
Pg 77 "But the TARDIS was more than just a time-and-space machine. She liked him, Fitz knew that. Long ago, she had done what all the king's horses and all the king's men couldn't do for Humpty Dumpty - put him back together again when one especially nasty misadventure had left him a different person." We saw this in Interference part II and Fitz learned about it in The Ancestor Cell.
Pg 88 "The TARDIS... when recreating him, she'd modelled him on the Fitz she remembered through her telepathic circuits" Interference, part II.
Pgs 89-90 "'Halcyon and Falsh had arranged tow fleets,' said Gaws bitterly. 'Captured each rock in a gravity field and dragged them out to the frontiers. Sold them. To the Kilomons, Draconians, pretty much anyone.'" The Kilomons are an uncertain reference. The Draconians appeared in Frontier of Space and Catastrophea. But see Continuity Cock-ups.
Pg 107 "I've been to Jupiter before! This big station called Farside, you must have heard of it?" Forward reference to upcoming Eighth Doctor PDA Fear Itself.
Pg 132 "Pent central have sent some hazard squad down there." Ten Little Aliens.
Pg 176 "It was squat, muscular, with a broad head, and from its silhouette it seemed to be wearing some kind of armour." A Sontaran (The Time Warrior et al).
Pg 177 "To his surprise, at one point he saw an adaptation of his Mechtlan layout being tried as a backdrop" Parallel 59.
Pg 181 "He'd seen whole worlds go up with less fuss." The Ancestor Cell and The Book of the Still.
Pg183 "High ridges at its shoulder flanked its barrel-like torso, and its head was a huge crystalline bud." A Kroton (The Krotons, Alien Bodies).
Pg 184 "A tall humanoid creature festooned with dangling fronds." Probably a member of Trantis's race (The Daleks Master Plan).
Pg 219 "Don't interrupt me when I'm monologuing" Misquote from The Curse of Fenric (special edition).
Pg 250 "Fitz woke up suddenly in his old place on Mechta, before things turned bad. [...] He would see Serjey today, maybe Anya. All his old friends..." Parallel 59.
Pg 266 "Tinya was being questioned by Pentagon Central." Pentagon Central is also important in Ten Little Aliens.
Pg 267 "Something the size of Jupiter will soon drag in all kinds of old flotsam and jetsam." Including Voga, planet of gold (Revenge of the Cybermen).
OLD FRIENDS AND OLD ENEMIES
Sontarans (pg 176), Krotons (pg 183) and (probably) Trantis's race, from The Daleks' Master Plan (pg 184).
NEW FRIENDS AND NEW ENEMIES
Salsa Sook, Aristotle Halcyon, Robart Falsh, the Ichthal representative, Tinya, Gaws and Mildrid (who are in no way related to 70s sitcom couple George and Mildred, despite having identical descriptions, oh no).
Pgs 61/144 An Icthal, a fish-like alien with grey skin, features bunched in the middle of its face and gills where its ears should be, but that walks upright with two legs and two arms.
Pg 174 Space slugs, genetically created slugs that instill aggression in other species.
Pg 184 A tall humanoid creature with dangling fronds, probably a member of Trantis's race (The Daleks Master Plan).
Pg 116 The Falsh Industries Luxury Orbiting Conference Podule (FILOC-P). Amusingly, it looks like a silver cotton reel surrounded by layers of vacuum-cleaner hose and looks to Trix as though it were made on Blue Peter. Which a number of space stations in the TV series had in common.